At some point in the ancient history of Geonosis, a comet crashed in one of the planet's many moons. The collision debris not only formed the famous rings of Geonosis, but also formed a field of small asteroids which would sometimes rain down on the planet's surface.[2]

The Geonosians took Kenobi captive, but he managed to dispatch a distress call to his superiors on Coruscant, the Jedi High Council. The Council then dispatched two hundred Jedi to Geonosis. Meanwhile, the Geonosians sentenced Master Kenobi to death in the Petranaki arena along with his apprenticeAnakin Skywalker, and the Republic senatorPadmé Amidala. Eventually, the Jedi reinforcements arrived, and quickly dealt with the Geonosian warriors. However, the immense droid army of the Confederacy was laying in wait, and many Jedi fell under enemy fire. When all seemed lost, even more reinforcements arrived, in the form of the newly created Grand Army of the Republic, which made use of clone soldiers. Upon the arrival of the clone army, the Republic and the Confederacy engaged in the first battle of what would later be known as the Clone Wars.[5]

Following the Battle near Dorin, the Republic sent Jedi General Ki-Adi-Mundi, Obi-Wan Kenobi, Luminara Unduli, and Anakin Skywalker to take Geonosis with a massive invasion. As they made their descent, Kenobi's and Commander Cody's force boarded their gunships and flew to secure the rendezvous point. However their gunships came under heavy fire from the Geonosians and their defenses. Mundi and Commander Jet's forces followed him but they were forced to land their AT-TEs away from the rendezvous due to the heavy fire. Skywalker's, Commander Ahsoka Tano's, and Captain Rex's gunships were shot down and all their AT-TEs were destroyed. Despite that, they continued towards to the rendezvous point and were met with heavy resistance from the Geonosians. Mundi's gunship was shot down and he was wounded. Commander Cody was able to land his AT-TEs, but the landing area came under fire from the Geonosians and their AATs. Kenobi's gunship was then hit and crash landed away from the landing zone. Only Kenobi and Trapper survived the crash and were then rescued by Waxer and Boil. Kenobi, Cody and their troopers then held the rendezvous awaiting Skywalker's and Mundi's forces.[9]

As Mundi's forces made their way through the Caltrop field to the rendezvous point, Jet contacted Admiral Wullf Yularen for air support. The Admiral however, could not divert any air support with risks to other units. Jet then left a squad with the AT-TEs and with Mundi and his clone flametroopers continued to the rendezvous. Skywalker and his force then came to a fortress that blocked their path. Skywalker and Tano then scaled the wall. They were able to destroy the battle droids, but they were then confronted by Droidekas who they were able to defeat with Rex's help. They then planted explosives inside the wall and their way was cleared. Skywalker's forces were then able to meet up with Mundi's forces. Skywalker then contacted Yularen for air support and Yularen was able to provide a squadron of bombers.[9]

As Kenobi's forces were being overrun, the bombers then took out the Geonosians' forces surrounding the rendezvous. Skywalker's and Mundi's forces then joined Kenobi's to plan the last part of their attack. Skywalker would attack the outer defenses of the fortress while Kenobi brought in the AT-TEs and Mundi the gunships. Skywalker, Tano and a squad were able to penetrate the shield. They then threw droid poppers at the fortress's proton cannons, disabling them. Kenobi then brought the AT-TEs in range of the shield generator and destroyed. After the shield went down, Mundi brought in the gunships and captured the remaining Geonosians. Kenobi and Mundi, along with the rest of their wounded, left to recuperate, leaving Skywalker, his apprentice, and their force to destroy the factory.[9]

To help Skywalker, Tano and their forces in destroying the factory, Unduli, along with her apprentice Barriss Offee and Commander Gree's41st Elite Corps came to assist in the attack. They devised a plan to destroy the primary droid factory. Unduli and Skywalker then marched their troops across the bridge, without cover to get Poggle's forces' attention. During his time their, Poggle and his tactical droid, TX-21 were running the factory at 50% capacity and had ten garrisons of droids ready to be deployed. The super tanks were not finished yet but would be ready. The droids were then deployed, marching across the bridge to fight the clones. As the two forces fought, TX-21 then sent in geonosians to attack from above. Despite this, Skywalker's and Unduli's forces were able to defeat the droids. However, Poggle, at the urging of TX-21, deployed the super tanks. As they moved in on the clones, Skywalker ordered their cannons to fire at it, to no affect. The super tanks rolled over the clones as they made their way across the bridge.[15]

As battle raged above, Offee and Tano were able to make their way through the catacombs to the main reactor. Unfortunately, Offee inadvertently woke one of the Geonosians, who informed Poggle and TX-21 of this. After planting the bombs, Offee and Tano were then confronted by Poggle, TX-21, their Geonoisans and a super tank. Tano then destroyed TX-21, but failed to even dent the super tank. Offee and Tano then fought the Geonosian to get their bombs back, but failed. When Tano was knocked out, Offee took the droid drivers and took control of the super tank. Both of them decided to use the tank to destroy the factory.[15]

As the super tanks moved across the bridge, Unduli and Skywalker planted explosives to make the tanks fall into the ravine. They were succesful in destroying the tanks. However, they were then confronted by more battle droids. Skywalker then contacted Tano, telling her to set the bombs off. However, they then used the tank, knowing it might kill them. They fired the tank at the reactor, and the factory collapsed, burying them inside the wreckage. Despite that, Skywalker and Unduli were able find their apprentices alive.[15]

Following the successful invasion, Jedi Master Luminara Unduli went in search of Poggle the Lesser, who had retreated into the catacombs of an ancient temple. While she and a trooper searched the temple, a sandstorm prohibited reinforcements from reaching their positions. While communicating with Masters Kenobi and Mundi via hologram, Unduli's clone trooper was killed by the undead hordes of the mysterious Hive Queen Karina the Great. Having been knocked unconscious and captured, the Jedi Master was taken before Karina. Jedi Kenobi and Skywalker came to her rescue; they were not far off when Luminara regained consciousness and wrestled her way out of the zombies' reach. Realizing what they were up against, she contacted Kenobi to warn him not to come after her, but was cut off as the zombies overwhelmed her. The Jedi disregarded her warnings and continued their search until they came upon Karina's abode, where they found Luminara in an energy trap for her to be infested with brain worms. With Kenobi and Commander Cody delaying the zombies and the Queen, Skywalker freed Unduli and the two captured Poggle. Cody and his troops shot down the cave support, burying the Queen and taking Poggle prisoner.[10]

By 3 BBY[20], the Death Star had been moved to another construction site. All that remained were a series of Imperial construction modules orbiting the planet Geonosis.[18] The Empire also used poison canisters to sterilize the planet as a security measure,[21] killing all but one of the Geonosian species.[22]

In 3 BBY, the Lothal rebel cell along with retired Clone trooperRex were sent on a mission to one of the construction modules after rebel intelligence discovered the Empire had been building something above the planet, which unknown to them was the Death Star. Upon arriving above Geonosis, the rebels conducted a planetary scan and discovered there was no life on the planet, much to their confusion. Once they arrived at the construction module, they were ambushed by ISBAgentKallus and several stormtroopers. After a brief skirmish aboard the station, the rebels escaped, however Kallus and the rebel Zeb were still locked in combat. Zeb boarded an escape pod and Kallus followed him in. The pod soon experienced an engine malfunction, causing it to crash on the icy moon of Bahryn. Striking an unlikely friendship, the Imperial agent and the rebel managed to overcome the cold and fend off two bonzami to survive. After a few hours, the rest of the rebels managed to locate them by tracking their transponder, however Kallus decide to stay behind and wait for the Empire. After saying their farewells Zeb left for the ship.[18]

In 2 BBY, Saw Gerrera and his Partisans undertook a mission on behalf of Rebel Command to investigate the disappearance of the Geonosian species. During the course of their mission, they were attacked by the Geonosian Klik-Klak, who mistook them for hostiles. Most of Saw's team were killed, leaving Saw as the sole survivor. After losing contact with Saw, SenatorBail Organa dispatched the Spectres rebel cell and Clone Captain Rex to complete Saw's mission. Upon arriving, they discovered that Imperial construction modules and debris they had seen the last time had been cleared away.[21]

While Hera stayed aboard the Ghost, Rex, Ezra Bridger, Kanan Jarrus, and Chopper searched the catacombs for Saw while Sabine Wren and Garazeb Orrelios investigated a deflector shield generator, which turned out to be the power source that Saw's team had reported before losing contact. After finding Saw, the Spectres and Rex agreed to help him capture Klik-Klak in order to find out what happened to the Geonosians. Following a prolonged pursuit, the rebels managed to capture Klik-Klak while Sabine and Zeb managed to recover the generator's deflector core.[21]

While Saw was hostile to Klik-Klak, Ezra managed to win the trust of the Geonosian. The rebels subsequently learned that Klik-Klak was the custodian of the last Geonosian queen egg. After some discussion, Kanan convinced Saw to return Klik-Klak to Geonosis after they had finished questioning him. The rebels' presence on Geonosis attracted the attention of an Arquitens-class command cruiser led by CaptainBrunson. After escaping two TIE bombers, Hera, Zeb, and Sabine flew the Ghost into an air shaft and rendezvoused with the other rebels and Klik-Klak.[21]

A fierce disagreement soon broke out between the Spectres, Rex, and Saw. The Spectres and Rex disagreed with Saw's plan to take Klik-Klak offworld for interrogation and harsh methods which included electrocuting him with a shocker. Following a struggle, Saw threatened to shoot the Geonosian queen's egg in order to obtain information from Klik-Klak. Before the argument could escalate, the rebels and Saw were forced to join forces to repel an Imperial boarding party consisting of Jumptroopers. To flee the Imperials, Hera took the Ghost into the depths of Geonosis.[21]

Upon reaching the bottom, the rebels and Saw discovered that the Imperial weapons division had perpetrated genocide against the Geonosians using poison canisters. Saw, experiencing a change of heart, freed Klik-Klak and allowed him to retreat underground with the Geonosian queen egg. The rebels then loaded some canisters as evidence for the Imperial Senate. The Ghost then managed to escape the shaft by firing proton torpedoes at Bronson's light cruiser. Despite fleeing into space, they lost the canisters in the process.[21]

Following their mission, the rebels were debriefed by Senator Organa and Commander Jun Sato. Despite losing the canisters, Organa reassured them that the images they took of the poison canisters could sway more systems to the rebellion. Sato also congratulated them for rescuing Saw and obtaining a deflector core. While Saw was disappointed that they had not discovered what the Empire was building on Geonosis, Kanan reassured them that they soon would.[21]

Following the Battle of Yavin, Skywalker, now the Sith Lord Darth Vader, returned to Geonosis. Having been one of only a few individuals to survive the destruction of the Death Star, Vader had been sanctioned by the Emperor, both as punishment and as part of a test for Vader. Finding himself in need of guaranteeable personal assets free from Imperial oversight; troops, credits and the like, Vader recruited the rogue archaeologistDoctorAphra and the assassin droidsBT-1 and 0-0-0 to assist him in building an army of unquestionably loyal battle droids. Vader soon arrived on the planet and his team infiltrated the lair of Karina the Great, who had hatched from the egg protected by Klik-Klak. An injury that had she had suffered before hatching had rendered her sterile, but her instinct to reproduce had influenced her to create a droidfactory to produce modified B1 battle droids as her "children". While BT-1 fired on the queen's droid workers, Vader and Aphra severed the queen from her factory, and Aphra used her starship, the Ark Angel, to blow a large hole in the roof of the lair so that Vader's own starship could then extract both the factory and Vader's team with a large crane. The captured droid factory began producing BX-series droid commandos for Vader, which he used to assault the research base of a rival Imperial operative named Cylo.[11]

Geonosis possibly evolved from the planet "Ttaz," a proposed location for Star Wars: Episode V The Empire Strikes Back.[23] In pre-production of Attack of the Clones, Geonosis was known simply as "rock planet", its landscape being a rugged world made of red soil and stone reminiscent of the real life planet Mars and the buttes and mesas of the American southwest.[24]